Shockproof x-ray unit window



Nov. 5, 1935. J. H. FINDLAY 2,019,602

SHOCKPROOF X-RAY UNIT WINDOW Filed Nov. 17, 1933 2 Sheets-Sheet 1INVENTOR J. H. F/lVDA/q Y ATTORN EY Nov. 5, 1935. J. H. FINDLAYSHOCKPROOF X-RAY UNIT WINDOW.

2 Sheets-sheaf. 2

Filed Nov. 17, 1935 MW w rrfikwrggli u J n i g a 41 M: i 1 1 M m a 25424 15 Z16 za- INVENTOR JTH. F/AQlt,

ATTORNEY Patented Nov. 5, 1935 UNlTED STATES PATENT F E John H. Findlay,Montclair, N. J., assignor to Westinghouse Lamp Company, a corporationof Pennsylvania Application November 17, 1938, Serial No. 698,421

Claims.

My invention relates to X-ray apparatus and particularly to what isknown to the art as shockproof X-ray units.

The expediency of providing a unit of this type 5 has long beenrecognized in the art in that the possibilities of an operator orpatient accidentally contacting any of the high voltage carrying partsis entirely eliminated. It is customary in a shockproof unit to immerseall high tension parts as well as the X-ray tube in a medium having ahigher dielectric characteristic than air, such for example as oil,which not only isolates all high tension carrying parts but alsopromotescompactness of the unit. Due to the high dielectric strength of theinsulating medium being higher than air not only can the various hightension carrying parts be spaced closer together but the X-ray tube canbe considerably shortened.

However, several disadvantageous features are inherent in structures ofthis type in that during operation of the unit the heat generated by theX-ray tube is transmitted to the surrounding dielectric medium causingexpansion thereof which must be compensated for in some manner.Moreover, the X-rays generated by the tube are projected through the oilwhich acts as a filter therefor and restricts the passage of some of theX-rays having short wave lengths. The unit is usually assembled at thefactory with the tube rigidly secured interiorly of the container and itnot infrequently happens that the tube is broken in transit.

It is an object of my present invention to provide a shockproof unit inwhich the X-ray tube is so positioned with respect to the container thatnone of the dielectric medium is disposed between the tube and casing.

Another object of my present invention is the provision of a shockproofunit in which the casing is provided with a resilient reentrant windowso disposed with reference to the ray projecting portion of the tubethat the dielectric medium is precluded from filtering any of thegenerated X-rays.

A further object of my present invention is the provision of ashockproof X-ray unit in which the casing is provided with a resilientreentrant window which so contacts the ray projection portion of theX-ray tube that none of the dielectric medium is disposed therebetweenwhich would tend to filter any of the generated X-rays and which alsofunctions as a shock absorber for th tube during shipment and operation.

Still further objects of my invention will become obvious to thoseskilled in the art to which it appertains by reference to theaccompanying drawings wherein:

Figure 1 is a vertical view partly in section and partly broken awayshowing a shockproof unit 5 constructed in accordance with my presentinvention.

Fig. 2 is a sectional view in elevation and on an enlarged scale of theconstruction shown in Fig. 1. 10

Fig. 3 is a sectional view in elevation and on an enlarged scale of a,modification which my present invention may take, and

Fig. 4 is a sectional view in elevation and on an enlarged scale ofstill another modification 15 which my invention may take.

Referring now to the drawings in detail I have shown in Fig. 1 a casing5 of metal which encases an X-ray tube 6 and a high tension transformer(not shown) for energizing the tube both 20 of which are immersed in acooling and insulating dielectric medium such as oil 1.

The X-ray tube may be supported by the casing in any suitable manner,such for example, as an annular collar 8 of an insulating material 25consisting of semi-circular sections fastened together as by set screws9. This collar is in turn provided with laterally projecting lugs I0disposed about its periphery and is arranged to be secured to thedepending end of an annular 30 flange l2 also of suitable insulatingmaterial, such as bakelite, hard rubber, porcelain or the like. Thisflange is cut away to allow the circulation of the cooling andinsulating material 1 about the X-ray tube and to form depending a5prongs I3 to which the lugs ll] of collar 8 are secured as by means ofset screws Hi.

The annular flange I2 is provided at its upper end with a portion l5ofincreased diameter and is joined to a metal ring it in any suitable man-40 ner, such as by rivets l I. Should it be desired to reinforce thecasing 5 at the point of connection of annular flange l2, with itsintegral metal ring iii, a further metallic ring I8 may be suitablysecured thereto, such as by means of rivets I9 45 and welded as at 2B.The X-ray tube having been first secured to the collar 8 by the setscrews with an opening therein and depending downwardly from thisopening is a cylindrical metallic member 24 in the form of a bellows. Acupshaped member 25 of suitable X-ray transparent material, such as alight atomic weight metal, glass, cellophane, or the like, is in turnsecured to the depending edge of the metallic bellows 24 and the bottomor base of this cup-shaped member 25 is slightly concaved to conform tothe contour of the glass envelope of the X-ray tube.

The resiliency oi the reentrant window formed by the bellows 24 togetherwith the configuration of the cup-shaped member 25 forces the latterinto firm substantially oil-tight contact with the envelope of the X-raytube thus preventing any of the oil 1 from being disposed between thetube and window and acting as a filter for any of the generated X-rays.

Moreover, should the collar 8 become slightly loosened during shipmentof the device injury to the X-ray tube is precluded by the reentrantwindow acting as a shock absorber. The X-ray tube 6 has its respectiveelectrode terminals connected to the source of energy therefor byconductors 26 and, during operation the heat generated by the tube istransmitted through the anode stem to a cooling radiator 2! exteriorlyof the envelope which is immersed in the oil i When the oil becomesheated to such an extent that expansion thereof occurs a second bellows28 is provided at any suitable location in the casing 5. This latterbellows is slightly more fiexible than that forming the reentrant windowin order that it may preferably compensate for the expansion oi the oil.This prevents the expansion of oil from causing the cup-shaped member 25to become disengaged and allowing oil to fiow between it and theenvelope. However, any tendency of expansion oi the glass walls of theenvelope or loosening thereof is entirely compensated for by theresiliency of the reentrant window.

In Fig. 3 I have shown a modification oi the structure just describedwhich differs therefrom only in the manner of engagement of thecupshaped member 25 with the envelope of the tube.

In this embodiment the member 25 is again of the same configuration butis provided with an annular groove into which is secured a ring 29. Thisring may be of soft rubber or some other composition not deleteriouslyafiected by the cooling and insulating dielectric medium 1 so that itforms a suction cup firmly adhering to the envelope of the tube thusforming substantially an oil tight seal and again preventing'any of theoil from being disposed between the reentrant window and the X-ray tube.

Fig. 4 shows my invention as adapted to a shock-proof unit utilizingwhat is known to the art as a double ended X-ray tube. In thisparticular modification the resilient reentrant window comprising thebellows 24 and cup-shaped member 25 are made integral with the casing 5and the latter is provided with an annular ring 30 formed by a thickenedportion of the casing. This ring is in turn threaded internally for thepurpose of enabling the engagement therewith of a ray opaque cone 32.Again the reentrant window comprises the bellows 24 and the cup-shapedmember 25 having a concave surface which firmly fits the contour of theenvelope of the tube at the point of emergence of the X-rays. Alsoanother bellows, such as shown at 28 Fig. 1, is provided in the casing 5which is of a more flexible nature than the reentrant window so thatthis latter bellows first compensates for the expansion of the oil 1.

Although I have shown in Figs. 1, 2 and 3, the reentrant window andX-ray tube as being detachably supported by the casing 5, in order thati the tube may be assembled and then inserted in the casing, it is to beunderstood that the reentrant window may be formed integral with thecasing as in Fig. 4 and the X-ray tube inserted through a detachablecover located elsewhere in 10 the casing. Moreover, the tube may besupported by the casing by any other suitable construction so long asthe ray projecting portion of the tube is in firm contact with thereentrant window.

It can thus be readily appreciated by those 15 skilled in the art that Ihave shown a shockproof X-ray unit in which all high tension parts areisolated to prevent accidental contact therewith by an operator orpatient. That by immersing the X-ray tube in a dielectric medium of mhigher strength than air I am enabled to utilize a ioreshortened tubeand by the employment oi a resilent reentrant window which firmlycontacts the envelope of the tube not only is the A dielectric mediumprecluded from being disposed :5 between the tube and window, but thewindow acts as a shock absorber for the tube during transit andoperation oi the unit.

Although I have shown and described several v modifications of myinvention I do not desire to so be limited thereto as various othermodifications may be made without departing from the spirit and scope ofthe appended claims.

What is claimed: r

1. In a shockprooi X-ray unit, the combination it with a casing, of anX-ray tube mounted therein and adapted when energized to generateX-rays,

a body of cooling and insulating material having a higher dielectricstrength than air immersing v said X-ray tube, and a reentrant X-raypervious 4.0 window in said casing adjacent the envelope of said tubethrough which X-rays emanate and having a yieldable portion with theremaining portion thereof conforming to the contour 0! said envelope forthe purpose 01 forming a firm con- 45 tact therewith to prevent theingress of dielectric medium therebetween and to absorb any shocks tosaid tube during operation or transit of said unit.

2. In a shockproof X-ray unit, the combination 50 with a casing, of anX-ray tube mounted therein and adapted when energized to generateX-rays,

a body of cooling and insulating material having a higher dielectricstrength than air immersing said X-ray tube, and a reentrant X-raypervious 55 window in said casing having a portion thereof firmlyengaging the envelope of said tube adjacent its ray projection portionto form substantially an oil tight seal and prevent the ingress of oiltherebetween, and said window having a do further portion thereoiyieldable in the direction of X-ray emanations for the purpose ofabsorbing shocks and any tendency of expansion by the envelope of saidX-ray tube.

3. In a shockproof X-ray unit, the combina- 5 tion with a casing, of anX-ray tube adapted when energized to generate X-rays, a body of liquidcooling and insulating material having a higher dielectric strength thanair in said, casing, areentrant member forming an oil tight 10 seal withsaid casing and extending inwardly thereof, means connected to saidreentrant member and to said casing for supporting said reentrantmember, means connected to said reentrant member and said X-ray tube forsupporting the latter interiorly of said casing and immersed in saiddielectric material, and a reentrant window supported by said firstmentioned means and firmly contacting the envelope of said,

X-ray tube to prevent any of said dielectric material being disposedtherebetween and acting as a filter for any of the generated X-rays.

4. In a shockproof X-ray unit, the combination with a casing, of anX-ray tube adapted when energized to generate X-rays, a body of liquidcooling and insulating material having a higher dielectric strength thanair in said casing, a detachable reentrant member of insulating materialextending inwardly of said casing and forming an oil tight sealtherewith, means connected to said reentrant member and to said casingfor supporting said reentrant member, means connected to said reentrantmember and said X-ray tube for supporting the latter interiorly of saidcasing and immersed in said dielectric material, and a reentrant windowsupported by said first mentioned means and provided with a portionthereof having a concavity conforming to the contour of the envelope ofsaid tube for the purpose of establishing a substantially oil tightcontact therewith to exclude said dielectric material and prevent thesame from filtering any of the generated X-rays.

5. In a shockproof X-ray unit, the combination with a casing, of anX-ray tube adapted when energized to generate X-rays, a body of liquidcooling and insulating material having a higher dielectric strength thanair in said casing, a detachable reentrant member of insulating materialextending inwardly of said casing and forming an oil tight sealtherewith, means connected to said reentrant member and to said casingfor supporting said reentrant member, means connected to said reentrantmember and said X-ray tube for supporting the latter interiorly of saidcasing and immersed in said dielectric material comprising a splitcollar surrounding the envelope of said tube and secured to saiddetachable reentrant member, and an X-ray pervious window supported bysaid first mentioned means and provided with a portion thereof having aconcavity conforming to the contour of the envelope of said tube for thepurpose of establishing a substantially oil tight connection therewithto exclude said liquid dielectric material and preventing the same fromfiltering any of the generated X-rays, and the remaining portion of saidreentrant window being yieldable in the direction of its longitudinalaxis in order to absorb any shock to said X-ray tube and to compensatefor any tendency of expansion of said envelope during operation.

JOHN H. FINDLAY.

